1. Technical Field
The present invention relates to a projector.
2. Related Art
A projector which uses a discharge lamp such as a high pressure mercury lamp or a metal halide lamp has been put into practical use. In such a projector, for example, a dimming technique as disclosed in JP-A-2007-41535 is used. As one of dimming techniques, there is a technique of performing dimming by controlling electric power supplied to a discharge lamp (hereinafter, referred to as “lamp dimming”).
Further, in recent years, a projector which uses a discharge lamp such as a high pressure mercury lamp or a metal halide lamp and outputs a stereoscopic image has been put into practical use.
As an example of a method of outputting the stereoscopic image, there is a method of switching and alternately outputting a right-eye image and a left-eye image (for example, an active shutter glasses type such as “XPAND beyond cinema (trademark of X6D Limited)”). In this method, the right-eye image is viewed with the right eye and the left-eye image is viewed with the left eye using active shutter glasses or the like which are synchronized with an image signal, and thus, the image is viewed stereoscopically using the parallax between the left eye and the right eye.
If a state where the electric power supplied to the discharge lamp is decreased due to lamp dimming is continued for a long time, the temperature of the discharge lamp is decreased, and thus condensation of metal (mercury or the like) in a light emitting tube of the discharge lamp may progress. If the condensation of metal (mercury or the like) progresses, in order to increase luminance again, time is necessary for evaporating the metal (mercury or the like) again. As a result, there is a problem that time is taken for increasing luminance (luminance responsiveness of the projector is deteriorated).
Further, if the temperature of the discharge lamp is decreased, an electrode of the discharge lamp cannot be sufficiently melted, and the electrode may be deformed. If the electrode is deformed, an arc starting point may be deviated from an original position, and thus, flicker easily occurs. If flicker occurs, the brightness of an image projected during usage of the projector is changed.